使用责任链模式实现中间件功能

<?php
abstract class BaseMiddleware
{
    protected $next_node = null;

    abstract public function handle(RequestInterface $request);

    final public function setNextMiddleware(BaseMiddleware $next)
    {
        $this->next_node = $next;
    }
}

<?php
class BeforeMiddleware extends BaseMiddleware
{
    public function handle(RequestInterface $request)
    {
        var_dump("Before Middle");

        if($this->next_node){
            $this->next_node->handle($request);
        }
    }
} 

<?php
class MiddleHandle
{

    private $middlewares = [
        "app\Http\Middleware\BeforeMiddleware",
        "app\Http\Middleware\NextMiddleware",
        "app\Http\Middleware\AfterMiddleware"
    ];

    private $first_obj;

    public function __construct()
    {
        $pre_obj = null;
        $next_obj = null;
        foreach ($this->middlewares as $v){
            if(!$pre_obj){
                $pre_obj = new $v;
                $this->first_obj = $pre_obj;
            }else{
                $next_obj = new $v;
                $pre_obj->setNextMiddleware($next_obj);
                $pre_obj = $next_obj;
            }
        }
    }

    public function dispatch(RequestInterface $request)
    {
        $this->first_obj->handle($request);
    }

}

root@2e26c1b5178c:/home/www/wwwroot/MySwoole# php index.php
string(13) "Before Middle"
string(11) "Next Middle"
string(12) "After Middle"